At least 26 people died and 88 were injured in an explosion and fire at a nightclub in the Romanian capital, where hundreds of people had gathered late last night, government officials said.

It's one of the city's worst incidents in decades.

The death toll may still climb at the club, which hosted a rock concert attended by up to 400, accordign to the Head of the Department of Emergency Situations at the Ministry of Internal Affairs, Raed Arafat.

One witness said there were fireworks inside the club. A pillar and the ceiling caught fire and then there was an explosion and heavy smoke.

Many of the injured reached local hospitals on their own, Arafat said, before heading to the hospital himself to check whether they were able to cope with the number of people arriving at their doors.

TV footage showed police officers and paramedics trying to resuscitate young people lying on the pavement while sirens wailed with more ambulances deployed to the scene.

Deputy Prime Minister Gabriel Oprea said an investigation into the cause of the incident was already underway.